Methods, apparatus, and systems for securing sim (subscriber identity module) personalization and other data on a first processor and secure communication of the sim data to a second processor

ABSTRACT

An electronic circuit  120  includes a more-secure processor ( 600 ) having hardware based security ( 138 ) for storing data. A less-secure processor ( 200 ) eventually utilizes the data. By a data transfer request-response arrangement ( 2010, 2050, 2070, 2090 ) between the more-secure processor ( 600 ) and the less-secure processor ( 200 ), the more-secure processor ( 600 ) confers greater security of the data on the less-secure processor ( 200 ). A manufacturing process makes a handheld device ( 110 ) having a storage space ( 222 ), a less-secure processor ( 200 ) for executing modem software and a more-secure processor ( 600 ) having a protected application ( 2090 ) and a secure storage ( 2210 ). A manufacturing process involves generating a per-device private key and public key pair, storing the private key in a secure storage ( 2210 ) where it can be accessed by the protected application ( 2090 ), combining the public key with the modem software to produce a combined software, signing the combined software; and storing the signed combined software into the storage space ( 222 ). Other processes of manufacture, processes of operation, circuits, devices, wireless and wireline communications products, wireless handsets and systems are disclosed and claimed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of prior application Ser. No.13/043,103, filed Mar. 8, 2011, currently pending;

Which was a Divisional of prior application Ser. No. 11/100,690, filedApr. 7, 2005, now U.S. Pat. No. 7,940,932, granted May 10, 2011;

Which claims the benefit of the filing date of Provisional ApplicationNo. 60/561,135, filed Apr. 8, 2004, entitled “Methods, Apparatus, andSystems for Securing SIM (Subscriber Identity Module) Personalizationand Other Data on a First Processor and Secure Communication of the SIMData to a Second Processor” to Erdal Paksoy, Narendar Shankar andSven-Inge Redin.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

This invention is in the field of information and communications, and ismore specifically directed to improved processes, circuits, devices, andsystems for varied levels of security and other information andcommunication processing purposes, and processes of making them. Withoutlimitation, the background is further described in connection withwireless communications processing.

Wireless communications, of many types, have gained increasingpopularity in recent years. Among other types of mobile equipment (ME),the mobile wireless (or “cellular”) telephone has become ubiquitousaround the world. Mobile telephony has recently begun to communicatevideo and digital data, in addition to voice. Wireless modems, forcommunicating computer data over a wide area network, using mobilewireless telephone channels and techniques are also available.

Wireless data communications in wireless local area networks (WLAN),such as that operating according to the well-known IEEE 802.11 standard,has become especially popular in a wide range of installations, rangingfrom home networks to commercial establishments. Short-range wirelessdata communication according to the “Bluetooth” technology permitscomputer peripherals to communicate with a personal computer orworkstation within the same room. Numerous other wireless technologiesexist and are emerging.

Security techniques are used to improve the security of retail and otherbusiness commercial transactions in electronic commerce and to improvethe security of communications wherever personal and/or commercialprivacy is desirable. Security is important in both wireline andwireless communications.

Processors of various types, including digital signal processing (DSP)chips and/or other integrated circuit devices are important to thesesystems and applications. Reducing the cost of manufacture and providinga variety of circuit and system products with performance features fordifferent market segments are important goals in DSPs, integratedcircuits generally and system-on-a-chip (SOC) design.

Coassigned U.S. Patent Application Publication 2004/0025010 of J. Azema,E. Balard, A. Chateau, E. Paksoy, and M. Leclercq, describes a computingplatform that binds system firmware to a particular computing platformusing a manufacturer certificate. A die identification number associatedwith an individual device is stored in a fused memory array (eFuse) atthe time of manufacture and can be compared with the manufacturercertificate to bind the code to the platform.

Further alternative, improved and otherwise advantageous solutions aredesirable in the art.

SUMMARY OF THE INVENTION

Generally, one form of the invention includes a first processor havinghardware-based security, a first memory coupled to the first processorand having data stored in said memory, a second processor having asecond memory and operable to authenticate the data in the firstprocessor, and the first processor operable upon completion of theauthentication to send the data from the memory of the first processorto a second memory external to the first processor.

Generally, another form of the invention involves an electronic circuitincluding a more-secure processor having hardware based security forstoring sensitive data, a less-secure processor that eventually utilizesthe sensitive data; and a data transfer request-response protocolbetween the more-secure processor and the less-secure processor for themore-secure processor to confer greater security of the sensitive dataon the less-secure processor.

Generally, a further form of the invention involves a process ofmanufacturing a cellular telephone having a storage space, a less-secureprocessor for executing modem software and a more-secure processorhaving a protected application and a secure storage. The manufacturingprocess involves generating a per-device private key and public keypair, storing the private key in a secure storage where it can beaccessed by the protected application, combining the public key with themodem software to produce a combined software, signing the combinedsoftware; and storing the signed combined software into the storagespace.

Generally, a still further form of the invention involves a systemincluding at least two more-secure processors having more-secureprocessing partitioned among said more-secure processors; and at leastone less-secure processor.

Other forms of the invention involving processes of manufacture,processes of operation, circuits, devices, wireless and wirelinecommunications products, wireless handsets and systems are disclosed andclaimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial diagram of a communications system includingsystem blocks, for example a cellular base station, a WLAN AP (wirelesslocal area network access point), a WLAN gateway, a personal computer,and two cellular telephone handsets, any one, some or all of theforegoing improved according to the invention.

FIGS. 2A-2G are block diagrams of inventive integrated circuit chips foruse in the blocks of the communications system of FIG. 1.

FIG. 2A is a block diagram of an integrated circuit including a digitalbaseband section, the integrated circuit provided on a printed circuitboard system of integrated circuit chips for use in one or more of thesystem blocks of FIG. 1.

FIG. 2B is a block diagram of an integrated circuit including an analogbaseband section, the integrated circuit provided on a printed circuitboard system of integrated circuit chips for use in one or more of thesystem blocks of FIG. 1.

FIG. 2C is a block diagram of an integrated circuit including a GSM/GPRSRF (radio frequency) unit, the integrated circuit on a printed circuitboard system of integrated circuit chips for use in one or more of thesystem blocks of FIG. 1.

FIG. 2D is a block diagram of an integrated circuit including a WCDMA(wideband code division multiple access) RF (radio frequency) unit, theintegrated circuit on a printed circuit board system of integratedcircuit chips for use in one or more of the system blocks of FIG. 1.

FIGS. 2E and 2F are two halves of a block diagram of an integratedcircuit including application processor circuitry, the integratedcircuit provided with off-chip peripherals on a printed circuit boardsystem of integrated circuit chips for use in one or more of the systemblocks of FIG. 1.

FIG. 2G is a block diagram of a WLAN integrated circuit including MAC(media access controller), PHY (physical layer) and AFE (analog frontend), the integrated circuit on a printed circuit board system ofintegrated circuit chips for use in one or more of the system blocks ofFIG. 1.

FIG. 3 is a block diagram of processors of FIGS. 2A and 2E with improvedsecurity processes for selectively operating a communications system forimproved security.

FIG. 3A is a diagram of identification (ID), certificates and hashes foran improved device bound certificate combination.

FIG. 4 is a more detailed system and process diagram of a process ofimproved security for operating a communications system using theprocessors of FIGS. 2A and 2E.

FIG. 5 is a partially block, partially process diagram for improvedsecurity using storage areas, a secure state machine and a processoroperated by a process having a user mode, a kernel mode, and a securemode.

FIG. 6 is a flow diagram of a booting process for use in the systems,processors and processes of FIG. 5.

FIG. 7 is a block diagram of a system for improved security using ahigher security processing block and a plurality of lower securityprocessing blocks.

FIG. 8 is a block diagram of a system for improved security using aplurality of higher security blocks and one or more lower securityblocks.

FIG. 9 is a block diagram of a system and process of manufacture oftarget devices such as cell phones using the device bound certificate ofFIG. 3A.

Corresponding numerals designate corresponding parts in the drawingsexcept where the context indicates otherwise.

DETAILED DESCRIPTION OF EMBODIMENTS

In FIG. 1 an improved communications system 100 has system blocks withselectively-determinable security level. Any or all of the systemblocks, such as cellular telephone and data handsets 110 and 110′, acellular (telephony and data) base station 150, a WLAN AP (wirelesslocal area network access point, IEEE 802.11 or otherwise) 160, a WLANgateway 180, and a personal computer (PC) 190, communicate with eachother in communications system 100. Each of the system blocks 110, 110′,150, 160, 180, 190 are provided with one or more PHY physical layerblocks and interfaces as selected by the skilled worker in variousproducts, for DSL (digital subscriber line broadband over twisted paircopper infrastructure), cable (DOCSIS and other forms of coaxial cablebroadband communications), fiber (fiber optic cable to premises), andEthernet wideband network. Cellular base station 150 two-waycommunicates with the handsets 110, 110′, and with the Internet, withcellular communications networks and with PSTN (public switchedtelephone network). Cellular base station 150 locally and/or remotelyinterfaces with Transaction Processing to support secure commercialcontent, secure financial services, and other services over cellulartelephone networks, over the Internet and on other networks.

In this way advanced networking capability for services and content,such as cellular telephony and data, audio, music, voice, video, e-mail,e-commerce, file transfer and other data services, internet, world wideweb browsing, TCP/IP (transmission control protocol/Internet protocol),voice over packet and voice over Internet protocol (VoP/VoIP), and otherservices accommodates and provides security for secure utilization andenjoyment appropriate to the just-listed and other particularapplications, while recognizing market demand for different levels ofsecurity. The embodiments, applications and system blocks disclosedherein are suitably implemented are suitably implemented in fixed,portable, mobile, automotive, seaborne, and airborne, communications,control, and other apparatus.

For example, handset 110 is improved for selectively determinablesecurity and economy when manufactured. Handset 110 remainsinteroperable and able to communicate with all other similarly improvedand unimproved system blocks of communications system 100. On a cellphone printed circuit board (PCB) 120 in handset 110, there is provideda higher-security processor integrated circuit 122, an external flashmemory 124, and a serial interface 126. Serial interface 126 is suitablya wireline interface, such as a USB interface connected by a USB line tothe personal computer 190 when the user desires and for reception ofsoftware intercommunication and updating of information between thepersonal computer 190 (or other originating sources external to thehandset 110) and the handset 110. Such intercommunication and updatingalso occur via a lower-security processor such as for cellular modem,WLAN, Bluetooth, or other wireless or wireline modem processor andphysical layer (PHY) circuitry 128.

Processor integrated circuit 122 includes at least one processor (orcentral processing unit CPU) block 130 coupled to an internal (on-chipread-only memory) ROM 132, an internal (on-chip random access memory)RAM 134, and an internal (on-chip) flash memory 136. A security logiccircuit 138 is coupled to secure-or-general-purpose-identification value(Security/GPI) bits 140 of a non-volatile one-time alterable ProductionID register or array of electronic fuses (E-Fuses). Such E-Fuses are anexample of an identification code storage holding an identificationvalue. These E-Fuses are programmed in different units of the handset110, 110′ to thereby provide a security identification store havingnon-volatile bits representing whether the wireless handset (or othersystem block) is a less secure (“GP” herein) type or more high-securitytype (“HS” herein). Depending on the Security/GPI bits 140, boot coderesiding in ROM 132 responds differently to a Power-On Reset (POR)circuit 142 and to a secure watchdog circuit 144 coupled to processor130. A device-unique security key is suitably also provided in theE-fuses or downloaded to other non-volatile, difficult-to-alter parts ofthe cell phone unit 110.

It will be noted that the words “internal” and “external” as applied toa circuit or chip respectively refer to being on-chip or off-chip of theapplications processor chip 122. All items are assumed to be internal toan apparatus (such as a handset, base station, access point, gateway,PC, or other apparatus) except where the words “external to” are usedwith the name of the apparatus, such as “external to the handset.”

ROM 132 provides a boot storage having boot code that is executable indifferent boot sequences. One or more of RAM 134, internal flash 136,and external flash 124 are also suitably used to supplement ROM 132 forboot storage purposes. Processor 130 is an example of circuitry coupledto the identification code storage 140 to execute a selected bootsequence from the boot code in the boot storage either for more-secureoperation or for less-secure operation of the processor.

Processor 130 is also responsive to one or more other inputs to executefurther selected boot sequences from the boot code, or boot modes in aboot sequence. These other inputs are suitably provided by hardware onthe PCB 120 connecting to a boot mode input pin of chip 122,configuration values stored in ROM 132 or other memories, and by thepower-on reset circuit POR 142. Further, the boot code in the bootstorage suitably includes code that loads software external to thewireless handset via the wireless interface(s) 128 and/or the serialinterface 126 into external flash memory 124 and internal flash memory136 depending on the selected boot sequence.

Processor 130 is coupled to the on-chip boot ROM 132, to the power-onreset circuit 142 and to the security identification bits 140 toselectively execute boot code depending on the non-volatile informationof the security identification bits 140. Processor 130 is responsive toa security identification value represented by the bits 140 to recognizeboot code and modem software code that is intended for that particularunit 110—in other words, “device bound.”

A secure watchdog circuit 144 automatically counts down to zero andhard-resets the circuitry 122, 124 unless properly-operating software inthe cellular telephone 110 periodically reloads the watchdog counter toprevent it from reaching zero. In this way, many software errors andmuch security hacking are minimized and obviated.

FIGS. 2A-2G illustrate inventive integrated circuits for use in theblocks 110, 110′, 150, 160, 180, 190 of the communications system 100 ofFIG. 1. The skilled worker uses, replicates and adapts the integratedcircuits to the particular parts of the communications system 100 asappropriate to the functions intended. For conciseness of descriptionand without limitation, the integrated circuits are described withparticular reference to use of all of them in the cellular telephonehandsets 110 and 110′ by way of example. Also, the architecture ofintegrated circuit 122 is suitably incorporated into one or more ofintegrated circuit 200 of FIG. 2A, integrated circuit 600 of FIGS. 2Eand 2F, and integrated circuit 800 of FIG. 2G, for instance.

It is contemplated that the skilled worker uses each of the integratedcircuits shown, or such selection from the complement of blocks thereinprovided into appropriate other integrated circuit chips, in a manneroptimally combined or partitioned between the chips, to the extentneeded by any of the applications supported by the cellular telephonebase station 150, personal computer(s) 190 equipped with WLAN, WLANaccess point 160 and WLAN gateway 180, as well as radios andtelevisions, fixed and portable entertainment units, routers, pagers,personal digital assistants (PDA), organizers, scanners, faxes, copiers,household appliances, office appliances, combinations thereof, and otherapplication products now known or hereafter devised in which increased,or decreased, selectively determinable security and economy ofcommunication are desirable.

In FIG. 2A, an integrated circuit 200 includes a digital baseband (DBB)block 210 that has a RISC processor (such as MIPS core, ARM processor,or other suitable processor), a digital signal processor (DSP) such asfrom the TMS320C55x™ DSP generation from Texas Instruments Incorporatedor other digital signal processor, and a Memory Controller interfacingthe RISC and the DSP to a Flash memory 222 and a SDRAM (synchronousdynamic random access memory) 226. On chip RAM 220 and on-chip ROM 230also are accessible to the processors via the memory controller.Security accelerators block 240 provide additional computing power suchas for hashing and encryption that are accessible, for instance, whenthe integrated circuit 200 is operated in a security level enabling thesecurity accelerators block 240 and affording types of access to thesecurity accelerators depending on the security level and/or securitymode. Digital circuitry 250 supports and provides interfaces for one ormore of GSM, GPRS, EDGE, and UMTS (Global System for Mobilecommunications, General Packet Radio Service, Enhanced Data Rates forGlobal Evolution, Universal Mobile Telecommunications System) wireless,with or without high speed digital data service, via the analog basebandchip 300 of FIG. 2B and GSM chip 400 of FIG. 2C. Digital circuitry 250includes ciphering processor CRYPT for GSM A51 and/or A52 ciphering orand/or other encryption/decryption purposes. Blocks TPU (Time ProcessingUnit real-time sequencer), TSP (Time Serial Port), GEA (GPRS EncryptionAlgorithm block for ciphering at LLC logical link layer), RIF (RadioInterface), and SPI (Serial Port Interface) are included in digitalcircuitry 250.

Digital circuitry 260 provides codec for CDMA (Code Division MultipleAccess), CDMA2000, and/or WCDMA (wideband CDMA) wireless with or withoutan HSDPA (High Speed Downlink Packet Access) (or 1xEV-DV, 1xEV-DO or3xEV-DV) data feature via the analog baseband chip 300 of FIG. 2B andthe CDMA chip 500 of FIG. 2D. Digital circuitry 260 includes blocks MRC(maximal ratio combiner for multipath symbol combining), ENC(encryption/decryption), RX (downlink receive channel decoding,de-interleaving, viterbi decoding and turbo decoding) and TX (uplinktransmit convolutional encoding, turbo encoding, interleaving andchannelizing.). Block ENC has blocks for uplink and downlink supportingthe F8 confidentiality algorithm and the F9 integrity algorithm of WCDMAor otherwise suitable encryption/decryption processes for thecommunications application.

Audio/voice block 270 supports audio, voice and voice-over-packet (VoPand/or VoIP) functions and interfacing. Applications interface block 275couples the digital baseband 210 to an applications processor 600 ofFIGS. 2E and 2F. Serial interface 280 interfaces from parallel on-chipdigital busses to USB (Universal Serial Bus) of a PC (personal computer)190. Serial interface 280 includes UARTs (universal asynchronousreceiver/transmitter circuit) for performing the conversion of databetween parallel and serial lines. Chip 200 is coupled tolocation-determining circuitry 290 for GPS (Global Positioning System),and to a USIM (UMTS Subscriber Identity Module) 295 or other SIM.

In FIG. 2B a mixed-signal integrated circuit 300 includes an analogbaseband (ABB) block 310 for GSM/GPRS/EDGE/UMTS which includes SPI(Serial Port Interface), digital-to-analog/analog-to-digital conversionDAC/ADC block, and RF (radio frequency) Control pertaining toGSM/GPRS/EDGE/UMTS and coupled to RF (GSM etc.) chip 400 of FIG. 2C.Block 315 is an analogous ABB for CDMA, CDMA2000, and/or WCDMA wirelessand/or any associated HSDPA data (or 1xEV-DV, 1xEV-DO or 3xEV-DV dataand/or voice) with its respective SPI (Serial Port Interface),digital-to-analog conversion DAC/ADC block, and RF Control pertaining tosaid CDMA types and coupled to an RF chip 500 of FIG. 2D. An audio block320 has audio I/O (input/output) circuits to a speaker 322, a microphone324, and headphones 326. Audio block 320 is coupled to a voice codec anda stereo DAC (digital to analog converter), which in turn have thesignal path coupled to the baseband blocks 310 and 315 with suitableencryption/decryption activated or not.

A control interface 330 has a primary host interface (I/F) and asecondary host interface to DBB-related integrated circuit 200 of FIG.2A for the respective GSM and CDMA paths. The integrated circuit 300 isalso interfaced via arrow E to the I2C port of applications processorchip 600 of FIG. 2E. Control interface 330 is also coupled via accessarbitration circuitry to the interfaces in circuits 350 and thebasebands 310 and 315. A power conversion block 340 includes buckvoltage conversion circuitry for DC-to-DC conversion, and low-dropout(LDO) voltage regulators for power management/sleep mode of respectiveparts of the chip regulated by the LDOs. Power conversion block 340provides information to and is responsive to a power control statemachine shown between the power conversion block 340 and circuits 350.

Circuits 350 provide a 32 KHz oscillator and 12 MHz oscillator forclocking chip 300. The oscillators have frequencies determined byrespective crystals 354A and 354B. Circuits 350 include a RTC real timeclock (time/date functions), general purpose I/O input/output, avibrator drive (supplement to cell phone ringing features), a USBOn-The-Go (OTG) transceiver, and touch screen interface. A touch screen356 off-chip is connected to the touch screen interface on-chip.Batteries such as a lithium-ion battery 358 and backup battery providepower to the system and battery data on suitably provided separate linesfrom the battery pack. When needed, the battery also receives chargingcurrent from the Battery Charge Controller in analog circuit 350 whichincludes MADC (Monitoring ADC and analog input multiplexer such as foron-chip charging voltage and current, and battery voltage lines, andoff-chip battery voltage, current, temperature) under control of thepower control state machine.

In FIG. 2C an RF integrated circuit 400 includes a GSM/GPRS/EDGE/UMTS RFtransmitter block 410 supported by oscillator circuitry 420 withoff-chip crystal 425. Transmitter block 410 is fed by baseband block 310of FIG. 2B. Transmitter block 410 drives an off-chip dual band RF poweramplifier (PA) 430. On-chip voltage regulators 440 maintain appropriatevoltage under conditions of varying power usage. Off-chip switchplexer450 couples to wireless antenna and switch circuitry in FIG. 2D and toboth the transmit portion 410, 430 in FIG. 2C and the receive portionnext described. Switchplexer 450 is coupled via band-pass filters 455 toreceiving LNAs 460 (low noise amplifiers) for 850/900 MHz, 1800 MHz,1900 MHz and other appropriate communication bands. Depending on theband in use, the output of LNAs 460 couples to GSM/GPRS/EDGE/UMTSdemodulator 470 to produce the I/Q outputs thereof (in-phase,quadrature) to the GSM/GPRS/EDGE/UMTS baseband block 310 in FIG. 2B.

In FIG. 2D an integrated circuit 500 supports CDMA (code divisionmultiple access), CDMA2000 and/or WCDMA (wideband CDMA), etc. at RF(radio frequency) in a receiver section 510 and a transmitter section550. The cellular telephone antenna of the cellular telephone handset110 couples to a switch unit SWITCH and bandpass filters 570 that inturn couple to the GSM circuits of FIG. 2C and the CDMA circuits of FIG.2D. The receiver output lines at upper left and transmitter input linesat lower left are all coupled to the WCDMA/HSDPA baseband block 315 inFIG. 2B.

In FIGS. 2E and 2F are illustrated two halves of the block diagram of anintegrated circuit chip 600 for applications (apps) processing andvarious off-chip peripherals. This apps processor is an example of amore-secure secure processor compared to less-secure modem processor 200of FIG. 2A and WLAN processor 800 of FIG. 2G. This apps processor issuitably provided by or in an OMAP™ product from Texas InstrumentsIncorporated or another apps processor. The acronym “MPU” laterhereinbelow is also used to refer to the more-secure processor. Some ofthe improvements herein are particularly advantageous when the appsprocessor has hardware-based security such as security logic 138 and atrue random number generator (RNG), and when the modem processor 200and/or 800 lacks these features. Remarkably, the more-secure features ofthe apps processor are conferred on the less-secure modem processor,with a considerable improvement in both security and economy of thesystem.

Beginning with FIG. 2E, on-chip are found a high-speed WLAN 802.11a/b/ginterface circuit 610 coupled to a WLAN chip 800 of FIG. 2G.

Further provided on chip 600 of FIG. 2E is an applications processingsection 620 which includes a RISC processor (such as MIPS core, ARMprocessor, or other suitable processor), a digital signal processor(DSP) such as from the TMS320C55x™ DSP generation from Texas InstrumentsIncorporated or other digital signal processor, and a shared memorycontroller with DMA (direct memory access), and a 2D (two-dimensionaldisplay) graphic accelerator. The RISC and the DSP have access viaon-chip extended memory interface (EMIF/CF) 630 to off-chip memoryresources 635 including as appropriate, SDRAM, mobile DDR (double datarate) DRAM, and flash memory of any of NAND Flash, NOR Flash, andCompact Flash. On-chip, the shared memory controller and DMA (directmemory access) in circuitry 620 interfaces the RISC and the DSP viaon-chip bus to on-chip memory 640 with RAM and ROM. The 2D graphicaccelerator is coupled to frame buffer internal SRAM (static randomaccess memory) 660.

Security logic 138 of FIG. 1 and FIG. 2E includes hardware-basedprotection circuitry, also called security monitoring logic or a securestate machine 2260 of FIG. 5. Security logic 138 is coupled to andmonitors busses and other parts of the chip for security violations andprotects and isolates the protected areas. Security logic 138 makessecure ROM space inaccessible, makes a Security Control Register SECCTRLinaccessible, makes secure RAM space inaccessible and establishes anyother appropriate protections to additionally foster security. In oneembodiment such a software jump from flash to secure ROM, for instance,causes a security violation wherein, for example, the security logic 138produces an automatic immediate reset of the chip. In anotherembodiment, such a jump causes the security monitoring logic to producean error message and a re-vectoring of the jump away from secure ROM.Other security violations would include attempted access to SecurityControl Register SECCTRL or attempted access to secure RAM space.

Further in FIG. 2E, security block 650 includes secure hardwareaccelerators having security features and provided for acceleratingencryption and decryption of any one or more types known in the art. Arandom number generator RNG is provided in security block 650. Among theHash approaches are SHA-1 (Secured Hashing Algorithm), MD2 and MD5(Message Digest version #). Among the symmetric approaches are DES(Digital Encryption Standard), 3DES (Triple DES), RC4 (Rivest Cipher),ARC4 (related to RC4), TKIP (Temporal Key Integrity Protocol, uses RC4),AES (Advanced Encryption Standard). Among the asymmetric approaches areRSA, DSA, DH, NTRU, and ECC (elliptic curve cryptography). The securityfeatures contemplated include any of the foregoing hardware andprocesses and/or any other known or yet to be devised security and/orhardware and encryption/decryption processes implemented in hardware orsoftware.

Improvements are suitably implemented as described especially inconnection with integrated circuit 122 of FIG. 1 and elsewhere herein asrelated to FIG. 2E processing section 620, security logic 138, securityblock 650, RAM and ROM 640, and EMIF/CF block 630 (Extended MemoryInterface and Compact Flash Interface).

Further in FIG. 2E, on-chip peripherals 670 include UART data interfaceand MCSI (Multi-Channel Serial Interface) voice interface for off-chipBluetooth short distance wireless circuit 690. Debug messaging andserial interfacing are also available through the UART. A JTAG emulationinterface couples to an off-chip emulator for test and debug.

Further in peripherals 670 are an I2C interface to analog baseband ABBchip 300 of FIG. 2B, and an interface 685 to applications interface 275of integrated circuit chip 200 having digital baseband DBB in FIG. 2A.Interface 685 includes a MCSI voice interface, a UART interface forcontrols, and a multi-channel buffered serial port (McBSP interface) fordata. Timers, interrupt controller, and RTC (real time clock) circuitryare provided in chip 600.

Further in peripherals 670 are a MicroWire (u-wire 4 channel serialport) and multi-channel buffered serial port (McBSP interface) tooff-chip Audio codec, a touch-screeen controller, and audio amplifier680 to stereo speakers. External audio content and touch screen (in/out)are suitably provided. Additionally, an on-chip USB OTG interfacecouples to off-chip Host and Client devices. These USB communicationsare suitably directed outside handset 110 such as to PC 190 (personalcomputer) and/or from PC 190 to update the handset 110.

A SIM (subscriber identification module) magnetic or smart integratedcircuit card 695 is inserted into the cellular phone 110 and coupled toprovide subscriber identification information directly to apps processor600. In some embodiments, SIM card 695 is omitted and the information issuitably coupled from USIM 295 in FIG. 2A via lines 685 to appsprocessor 600 of FIG. 2E. In other embodiments where a SIM card is used,the USIM card 295 is omitted and SIM card 695 is directly coupled toapps processor 600.

Turning to FIG. 2F, chip 600 includes further interfaces and features.Note that the block diagram of FIGS. 2E and 2F is understood asproviding on-chip peripheral bussing and couplings between theapplication processing circuitry 620 and the various on-chip peripheralblocks, regardless of whether the diagram lacks explicitly-shown bussesand couplings, as is understood by the skilled worker.

An on-chip UART/IrDA (infrared data) interface 710 couples to off-chipGPS (global positioning system) and Fast IrDA infrared communicationsdevice. An interface 720 provides EMT9 and Camera interfacing to one ormore off-chip still cameras or video cameras 730, and/or to a CMOSsensor of radiant energy, and/or to a debugger.

Further in FIG. 2F, an on-chip LCD controller and associated PWL(Pulse-Width Light) block 740 are coupled to a color LCD display and itsLCD light controller off-chip. Further, on-chip interfaces 750 arerespectively provided for off-chip keypad and GPIO 760, on-chip LPG (LEDLight Emitting Diode Pulse Generator) and PWT (Pulse-Width Tone)interfaces are respectively provided for off-chip LED and buzzerperipherals 770. GPIO 760 has several chip pins for inputs.

On-chip MMC/SD multimedia and flash interfaces are provided for off-chipMMC Flash card, SD flash card and SDIO peripherals 780. An on-chipselectable-mode HDQ or 1-Wire (hardware protocols) battery monitoringserial interface module is provided for monitoring the off-chip Battery.On-chip Clock and Reset management circuitry 790 (coupled also to POR142 of FIG. 1) is connected to off-chip 12 MHz and 32 KHz crystals andto a reset pushbutton switch 795.

In FIG. 2G, a WLAN integrated circuit 800 includes MAC (media accesscontroller) 810, PHY (physical layer) 820 and AFE (analog front end)830. PHY 820 includes blocks for BARKER coding, CCK, and OFDM. PHY 820receives PHY Clocks from a clock generation block supplied with suitableoff-chip host clock, such as at 13, 16.8, 19.2, 26, or 38.4 MHz. Theseclocks are often found in cell phone systems and the host application issuitably a cell phone or any other end-application.

AFE 830 is coupled by receive (Rx), transmit (Tx) and CONTROL lines toan off-chip WLAN RF circuitry 840. WLAN RF 840 includes a 2.4 GHz(and/or 5 GHz) direct conversion transceiver and power amplifer and haslow noise amplifier LNA in the receive path. Bandpass filtering couplesWLAN RF 840 to a WLAN antenna.

In MAC 810, Security circuitry 850 supports any one or more of variousencryption/decryption processes such as WEP (Wired Equivalent Privacy),RC4, TKIP, CKIP, WPA, AES (advanced encryption standard), 802.11i andothers.

The security circuitry and processes depicted in FIGS. 1, 3, 4, 5 and 6are suitably provided by more-secure apps processor 600 and theirbenefits conferred on cellular modem processor 200 of FIG. 2A and/orconferred on WLAN security block 850 and WLAN processor 860 of FIG. 2G.In this way security of cellular telephone, data and videocommunications, voice-over-packet, and other voice, audio, video,financial, content and other services over all types of wireless andwireline physical layers (PHYs) are enhanced.

Further in FIG. 2G, processor 860 comprised of an embedded CPU (centralprocessing unit) is connected to internal RAM and ROM and coupled toprovide QoS (Quality of Service) IEEE 802.11e operations WME, WSM, andPCF (packet control function). Security block 850 in FIG. 2G has busingfor data in, data out, and controls interconnected with CPU 860.Interface hardware 870 and internal RAM on-chip couples CPU 860 with(see FIG. 2E) interface 610 of applications processor integrated circuit600 of FIG. 2E.

The description herein next turns to the considerations noted above andprovides further detailed description.

The apps processor has hardware based security which can be used forstoring SIM personalization data. SIM (Subscriber Identity Module)refers to a smart card identification of the user in GSM wireless. HW(hardware) security makes it possible to meet new GSMA (GSM Associationin wireless) regulations on tamper-protection (and confidentiality) ofthe SIM personalization information. The apps processor, which storesthe personalization data, has to work with a Modem Processor, whichcould be the modem side in a device like an OMAP730/850 device havingboth an apps processor and modem processor or a separate modem processoror other processor. It is the Modem Processor that eventually consumesthe SIM personalization data. In such scenarios, it becomes necessary tohave a protocol between the Modem processor and apps processor which cansecurely transfer the SIM personalization data to the Modem processorside.

This protocol can be also be used for secure transfer of otherinformation (like IMEI) from the apps processor side to the Modemprocessor side. IMEI refers to International Mobile Equipment Identifierwhich identifies the mobile equipment unit.

The Solution has 2 Aspects

Protocol Aspects:

The SIM personalization data transfer protocol is based on a requestresponse paradigm between the Modem Processor and the apps processor.The Modem side makes a request for the SIM personalization data, whichpasses through a Mailbox or other modem processor communicationsinterface and goes to the apps processor side, where an applicationinterfaces with the Secure Driver, which in turn loads a ProtectedApplication (PA) to perform the specific request. The response is routedback along the same path. In essence, as secure mode is concerned, theModem Processor software almost runs like an application on the appsprocessor side.

Security Aspects

1. Secure Tamper-proof Storage—the SIM personalization data is stored onthe apps processor side using secure storage available in the appsprocessor side. This secure storage is protected by HW based security.

2. Authentication—The Modem side software authenticates the response(containing the SIM personalization data), which comes from the Appsprocessor side. This is done by programming a private key (protected byHW security) on the factory floor on the apps processor side and thecorresponding Public Key (PK) on the Modem Processor software side. Arandom challenge protocol is run at every request, where the Modemprocessor sends a random challenge. This random challenge isconcatenated to the response (SIM Personalization Data) and signed bythe apps processor side. The Modem side software verifies the signedrandom challenge and SIM personalization data. Advantageously, ModemSoftware and the Public Key in the Modem Software are authenticated atboot time by the apps processor and are locked down (possible in OMAP7x0processor combinations, and OMAP850 processor combinations) orperiodically authenticated from the apps processor side (using the appsprocessor run-time security mechanisms). This also means that the ModemSoftware is accessible from the apps processor side (for reading only).

3. Confidentiality—If the response sent by the apps processor has to beconfidential (this is preferable for the SIM personalization data), theModem SW generates a Session Key and it encrypts the Session Key withthe Public Key. The Session Key is subsequently decrypted with thePrivate Key on the apps processor side and the Session Key is then usedto encrypt the SIM personalization data, which is sent to the ModemProcessor. In cases where there is no hardware security or true randomnumber generator on the Modem processor, code obfuscation techniques aresuitably used to make the software tamper-resistant. Obfuscation is asoftware method wherein symbols and information are scrambled in placeor dispersed throughout a file or files. All of this is done in such away that an authorized user can recover the original symbols andinformation by an appropriate reverse procedure or algorithm. Bycontrast, an unauthorized user without the reverse procedure oralgorithm is substantially impeded or prevented from recovering theoriginal symbols and information.

The protocol above can also be used to transfer other information (likethe IMEI (International Mobile Equipment Identifier), which is stored inthe apps processor side in a device bound manner) from the appsprocessor side to the Modem Processor. In some cases (like IMEI),confidentiality may not be needed.

This fast, efficient, secure solution leverages present ROM code and HWbased security mechanisms to store SIMLock Personalization data andprotect IMEI and securely communicate them to the Modem Processor.SIMLock is a feature that limits a cell phone to operate with onlycertain SIM cards from particular providers. This is one of the mostrobust ways of meeting the GSMA requirements.

GLOSSARY

ADL Auxiliary Download. A method used when flashing is done via IR orBluetooth. Memory ROM Code mechanism that consists of executing anBooting Initial SW from external memory Peripheral ROM Code mechanismthat consists of polling selected Booting interfaces, downloading andexecuting an Initial SW (in this case called Downloaded SW) in internalRAM. IMEI International Mobile Equipment Identifier. A globalidentification number in the GSM world. Pre-Flashing Pre-Flashing is aspecific case of Peripheral Booting, when the ROM Code mechanism is usedas part of a Flashing process to program external memories Initial SW SWwhich is executed by any of the ROM Code mechanisms (Memory Booting orPeripheral Booting). Initial SW is a generic term for Bootstrap andDownloaded SW Bootstrap Initial SW that is launched by the ROM Codeduring the Memory Booting phase. Downloaded Initial SW that isdownloaded into internal SRAM by the SW ROM Code during PeripheralBooting phase Flash Loader Downloaded SW launched by the ROM Code inPre- Flashing and which programs an image into external memories.Certificate Data block plus trusted signature of the data block. KeyCertificate Certificate where the data block contains the PK's includinga Public Key, Private Key pair for an asymmetric process. R&DCertificate where the data block contains development Certificateconfiguration parameters. SW Certificate Certificate where the datablock contains the Software digest, which can be related to PPA, PA orInitial SW PA Protected Application. An application that is executedinside Secure Environment. PPA Primary Protected Application. PersistentApplication present in Secure RAM after boot. OEM Original EquipmentManufacturer SSL Secure Sockets Layer Protocol-Cryptographic Protocolused to establish Session Keys HMAC Hashed Message Authentication Code

Introduction

The OMAP™ family of processors from Texas Instruments Incorporated,Dallas, Tex. includes processors like the OMAP16xx, OMAP17xx, OMAP7x0,OMAP850, OMAP24xx families, etc. The OMAP16xx, OMAP17xx and OMAP24xxfamilies are stand alone Applications (Apps) Processors but the OMAP7x0and OMAP850 families are integrated Apps and Modem processors.

While the apps processor has hardware based security, many modemprocessors do not. However, the modem processor is usually theprocessor, which transmits the IMEI number and is also linked to the SIMcard etc. Hence it becomes necessary to create a secure channel ofcommunication between the Modem and Apps processor.

This document outlines such approaches to securing communication byusing a simple message passing scheme between the two processors. Inparticular, this document outlines how the IMEI number can be verifiedon the Apps Processor side and be communicated to the Modem processorside, in a secure Manner. This secure communication channel can also beused for other purposes (like SIMLock etc).

Threat Models

This section outlines the various types of Apps Processor-ModemProcessor combinations and outlines the various threats in each case.

Type 1—This includes a processor like OMAP16xx, OMAP17xx or OMAP24xxprocessor, which has hardware security and works in conjunction with aModem Processor which does not have any hardware security. For suchcombinations, when the Modem side processor tries to fetch a verifiedIMEI number from the Apps Processor, an attacker scenario includes anattempt to hijack the software (which transmits the IMEI number) on theApps processor side. If the Modem processor software is an addressspace, which can be accessed by the Apps processor side, an attackerscenario includes an attempt to also hijack the Modem processorsoftware.

Type 2—This includes processors like OMAP7x0 and OMAP850 devices, wherethe Apps processor and Modem processor are integrated. The threat modelis the same as the Type 1 combination

Type 3—This includes processors like OMAP16xx, and OMAP17xx devices witha processor which has some amount of hardware based security. The threatmodel is the same as the earlier types but the Modem software isprobably not as vulnerable in this case as it can be secure through thehardware security in the modem processor.

Type 4—This includes processors like OMAP16xx, OMAP17xx, or OMAP24xxdevices with a separate Modem processor. The threats are the same asType 1.

Communication Protocol Option 1

This section describes a communication protocol between the ModemProcessor and Apps processor with the relevant security considerations.The assumption made here is that the Apps processor is the one whichstores the IMEI, SIMLock details etc (using hardware based security) andthe Modem processor requests information from the Apps processor side.The reason for doing so is that-for all types other than type 3 (andsome instances of Type 4 if there are any), the Modem side cannotprovide hardware based security and it becomes necessary to use the Appsprocessor's hardware based security.

For the type 3 combination, it is also possible to store all theinformation (like IMEI, SIMLock details etc) on the Modem processor sideand leverage the Modem Processor's hardware security features.

Storing and validating (at boot time and run-time) the IMEI on the Appsprocessor use Protected Applications (PAs), which run in a hardwarebased Secure Execution Environment. The Protected Applications can beaccessed through a software interface using a driver on the AppsProcessor side. FIG. 3 shows how this can be extended into a paradigmfor communication with the Modem processor. The flow happens in thesteps as shown in FIG. 3.

1. The Modem side software, which needs the IMEI number (or other SIMinformation) requests for this information from the Apps processor sideusing a MailBox or other communications path between the processors.This request is passed on from the other end of the MailBox or othercommunications path to a service routine on the Apps processor side.

2. The service routine passes the request to a driver through an APIcall. The driver, also called the SE (Secure Environment) Device Driveris an OS specific driver.

3. The driver loads a Protected Application (PA), which executes in ahardware protected execution environment, and passes the request to thePA.

4. The PA does the necessary validation of the IMEI and sends the IMEInumber (or any other requested information) to the driver

5. The driver passes this information to the service routine

6. The service routine passes this information to the Modem sidesoftware.

Security Considerations

-   -   1. The Driver, the Service routine need to be authenticated at        boot-time and periodically at run-time. This can be done using        the security mechanisms provided in the apps processor.    -   2 The modem side software needs to be authenticated at boot-time        and periodically at run-time. This is possible only if the Modem        side software is accessible by the Apps processor at boot-time        and at run-time. On platforms like an OMAP7x0 or OMAP850 device,        boot-time authentication of the Modem side software (using the        Apps processor) is sufficient as it can be locked down in a        write protect region after boot-time.    -   3. The modem side software has to trust that the IMEI        information (or any other information) that it has requested for        from the Apps processor side is authentic. This can be        accomplished in an end-to-end manner as follows:

While flashing the phone, a per-device private-key, public-key pair isgenerated (or injected into the phone). The private key is stored insecure storage in a manner where it can be accessed by the IMEI PA. Thepublic key is made a part of the Modem side software (part of the code)before it is signed and flashed.

As mentioned above, the Modem software is advantageously authenticatedat boot-time and periodically at run-time. This ensures that the publickey in the Modem side software is not tampered with (on OMAP7x0 andOMAP850 devices, the public key is locked down).

In the above protocol, in step 1, the Modem side SW sends a randomchallenge (which is carried over in steps 2, 3 to the PA). In step 4,along with the requested information, the PA also sends a signature ofthe random challenge, IMEI and any other result information to thedriver (The IMEI and result information is concatenated in apredetermined manner to the random challenge). This is passed in step 5to the service routine and in step 6 to the Modem side software. TheModem side software verifies the Signature(s) using the Public key,which it was programmed with. The Modem side software verifies therandom challenge. This verification mechanism is resistant toman-in-the-middle attacks, so long as the public key on the Modem sidesoftware is not tampered with. This again, as mentioned above needs b)to hold true.

Option 2

This section describes an enhancement to the DBC (Device BoundCertificate) scheme and provides a method for incorporating the Modemsoftware code in the device bound certificate. The new DBC format isshown in FIG. 3A. The DBC is again created at flashing time. Itincorporates the hash of the Modem SW certificate (which has been signedwith the OEM key) in the DBC. There is suitably provided a separateasymmetric cryptographic communications process at flashing time whereinthe Private Key of that asymmetric process is an OEM key held privatelyat OEM original equipment manufacturer, and the Public Key of thatasymmetric process is manufactured into or sent down to apps processorand called a Root Public Key for verifying the device bound certificateDBC and thus software integrity at flashing time by apps processor. Theprivate-key, public-key pair sent to target to provide securecommunications between more-secure apps processor and less-secure appsprocessor is a different subject discussed elsewhere herein. In theflashing asymmetric process, the DBC is verified at boot time and apartfrom the verification of the IMEI cert, the Modem SW certificate is alsoverified. The DBC is stored in an area of flash accessible by the ModemSoftware. This DBC is also verified at two other instances:

1. Periodically at run-time

2. The DBC verification is initiated by the Modem SW every time it wantsto use the IMEI number. It follows the same steps outlined in FIG. 1.Again the random challenge protocol should be used so that the responsefrom the Apps processor side is not tampered with.

Again as mentioned earlier, in the case of OMAP7x0 and OMAP850 devices,once the DBC has been authenticated at boot time, if both the Modem SWand the DBC have been locked down using flash write protect, there is noneed for run-time authentication. The boot time verification result hasto be stored in the region of SDRAM, which is write protected.

Example Solutions-IMEI and SIMLock on OMAP7x0, OMAP850 devices

This section focuses on the solutions as applicable on an integratedModem/Application processor devices such as the OMAP750 device andOMAP850 device, where the security features can be summarized asfollows:

1. The Application Processor has a HW secure environment with secureRAM, public key information and random secret keys such as DerivedKey(s) derived from a Device-Unique Secret Key as defined laterhereinbelow, embedded in hardware and has the ability to executeprotected applications (PAs). It is also equipped with a hardware randomnumber generator.

2. The Modem processor does not have a HW secure environment, nor doesit have a random number generator.

3. The Application Processor, when operating in the secure environment,can write-protect the modem side memory, so that no application runningon the application processor can modify the contents of the memorycontaining the modem side SW or data.

IMEI Protection

IMEI protection can easily be done using option 2 in the followingsteps.

1. While flashing the device, the DBC is created with the hash of theBootStrap and the Modem Software and the IMEI certificate and providedwith a Signature as the encrypted hash value of BootStrap, ModemSoftware and IMEI certificate combined or multiple encrypted hash valuesfrom hashes of various parts of the foregoing. If needed the IMEIcertificate can be obtained online

2. When the phone boots up, the boot time PA verifies the DBC and writeprotects the Modem SW code and the DBC. Note that the DBC and hence theIMEI is no longer in the FFS (Flash File System).

3. At run time, the Modem SW uses the IMEI directly from the DBC (notethat there is no verification needed with the Apps processor as theModem SW and the DBC containing the IMEI have been locked down).

4. The GSM edge data in SDRAM (Synchronous Dynamic Random Access Memory)is write protected from the MPU (done using GSM Protect). Apart from theabove the GSM/EDGE (wireless protocol) FFS (Flash File System) backup inflash is encrypted and the Working set of the GSM FFS in SDRAM is writeprotected from the MPU (done using GSM Protect). This is all donethrough PAs.

SIMLock Protection.

For SIMLock, the personalization data including keys has to be protectedagainst tampering and also needs to be confidential. The best way to dothis is to use the secure mode on the MPU side to do this. The protocolcan be implemented using option 1 as follows.

1. The Modem side software, which needs the personalization datarequests this information from the Apps processor side using a MailBoxor other communications path between the processors. This request (alongwith a random challenge) is passed on from the other end of the MailBoxor other communications path to a service routine on the Apps processorside.

2. The service routine passes the request to a driver through an API(Application Peripheral Interface) call. The driver, also called the SE(Secure Environment) Device Driver is an OS (Operating System) specificdriver.

3. The driver loads a Protected Application (PA), which executes in ahardware protected execution environment, and passes the request to thePA.

4. The PA does the necessary decryption of the personalizationinformation (stored in secure storage). The PA signs the personalizationinformation concatenated along with the random challenge (as describedin Option 1) and sends it to the driver

5. The driver passes this information to the service routine

6. The service routine passes this information to the Modem sidesoftware

7. The Modem SW verifies the signature and the random challenge.

The above protocol further provides confidentiality of thepersonalization data when it is being transmitted outside Secure Mode.Here security is further improved by using a mechanism where the ModemSW generates a Session Key, such as a random symmetric key from a randomseed (which is generated by the apps processor and stored in the ModemSW side) using an obfuscated key generation algorithm, encrypts thesymmetric key with the Public Key (which has been locked down on theModem Side SW as described in Option 1). Another method embodiment usesa combinatorial scheme of both code and data obfuscation, where the codeand data (the key such as the Session Key in this case) are bothobfuscated. Only the corresponding private key inside the Secure Mode onthe apps side can decrypt this Symmetric Key. The decrypted SymmetricKey is used to encrypt the personalization data from the PA right up tothe Modem SW. The Modem SW can then decrypt the personalization datausing the Symmetric Key possessed by the modem processor. All this isunder the assumption that there is no region of SDRAM which can actuallybe protected from an MPU read.

Note: In cases where the Modem processor has a HW secure environment anda random number generator, these are suitably used to improveconfidentiality: the random symmetric key is then generated by therandom number generator and used exclusively inside the Modem-side HWsecure environment. If the Modem processor has a HW based secureenvironment, any other applicable symmetric or asymmetric key basedprotocols for authenticated and confidential data transfer are suitablyused.

In the description above, “Write protected from the MPU” refers to theapps processor executing write protect operations in secure mode so thatneither the apps processor 600 and the modem processor 200 can alter thewrite-protected information.

Note these particular types of symmetric keys and numbers to distinguishaccording to the teachings herein.

A Device-Unique Secret Key is is a symmetric key, randomly generated andburned in an E-fuse on the chip during manufacturing. This device-uniquesecret key is the root of all, or an important basis of, confidentialityin the system.

A Derived Key is a symmetric key derived from the Device-Unique SecretKey. Many such Derived Keys can be derived during the lifetime of thedevice. A Derived Key is used to encrypt data to be placed in securestorage. (“Secure storage” is the process of encrypting data using sucha key and saving it in a non-volatile memory.)

A Random Seed is a random number generated by the random numbergenerator RNG in the more-secure processor at boot time and stored inthe less-secure processor memory (e.g. modem processor memory) forfuture use. The modem processor can use this Random Seed to generate“challenges” using a pseudorandom number generator of the modemprocessor.

A Session Key is a random number generated by modem processor software,see “Security Aspects 3. Confidentiality” earlier hereinabove. A SessionKey is a symmetric key used to establish a secure communication channelbetween the more-secure processor and the less-secure processor. TheSession Key is communicated from the less-secure processor to themore-secure processor by encrypting the Session Key with the public keyat the less-secure processor. The more-secure processor then uses thecorresponding private key of the more-secure processor inside the secureenvironment of the more-secure processor to decrypt the encryptedSession Key. The more-secure apps processor then uses the Session Key toencrypt the personalization data and/or device identification dataand/or other sensitive data before sending any one, some or all of thethus-encrypted sensitive data to the less-secure modem side.

Discussion now turns to an asymmetric cryptographic communicationsprocess used herein. A Private Key and a Public Key are provided as aprivate-key, public-key pair for use in the process. These keys arecalled asymmetric keys. The Private Key is kept secret. The Public Keycan be held less-secure. In an asymmetric cryptographic process, aprivate key is used to decrypt what a public key has encrypted. This iscalled public key encryption. In the assymetric process, both theprivate key or public key can decrypt what the other key hasencrypted—encrypt with one key, decrypt with the other key. Both keyscan be kept secret and used to establish a confidential channel, butthis result can be accomplished with symmetric keys also, at lower cost.Use of asymmetric cryptography herein is advantageous because one of thekeys can be disclosed, and that key is called the Public Key. The PublicKey can be used, for instance, in either or both of encryption andsignatures. In encryption, the process encrypts with the Public Key anddecrypts with the Private Key. Only the person who holds the Private Keycan decrypt. By contrast, encrypting a message with the Private Keymeans that anyone who possesses the Public Key can decrypt the message.Signatures operate such that only the person who holds the Private Keycan sign, and anyone holding the Public Key can verify. However, thePublic Key used to verify the signature must be valid. Accordingly, thePublic Key is provided in a certificate (see discussion of Device BoundCertificate DBC elsewhere herein) that is generated by a trusted source.

Next, a signing process is described. A signing process at a sendingside for signing sensitive data such as device identification dataand/or personalization data has steps of:

1—Hash the data at the sending side to get an original hash value Hash.2—Encrypt the hash value Hash (not necessarily the data) with a privatekey at the sending side. The encryption thwarts a man-in-the-middleattack that changes the data, computes a hash value HashX for that dataand then cannot encrypt the hash value HashX because theman-in-the-middle lacks the private key securely possessed by thesending side with which to perform the encryption. The Signature is theencrypted hash value from the sending side. The Signature is transmittedfrom the sending side along with the data. The data is not necessarilyencrypted but can be encrypted as well.

A verification process at a receiving side has steps of:

1—Hash the data at the receiving side to get a hash value Hash1.2—Decrypt the Signature at the receiving side, meaning decrypt theencrypted hash value Hash received from the signing process, with thecorresponding public key to get a hash value Hash2 at the receiving sidethat is presumably the same as the original hash value Hash from thesigning process.3—If Hash1=Hash2, the Signature is regarded as valid. This is becausethe receiving side has independently hashed the data to check for adiscrepancy indicating a man-in-the-middle attack. The receiving sidepossesses the public key (that for purposes of the asymmetric processcorresponds to but differs from the private key on the sending side)with which to decrypt the original hash value Hash. If Hash1 does notequal Hash2 then the communication received and purporting to be fromthe sending side is not regarded as valid. Either the Signature is notwhat was sent by the sending side or the data has been altered prior toreception or both. Either case is regarded as a signature-not-validsituation.

Among other embodiments, two alternative process embodiments forcommunication are described in connection with FIGS. 3, 4 and 5. Theyare summarized next.

Method 1 has the modem processor send a random challenge. Then the appsprocessor sends personalization data concatenated with random challengereceived from modem, both in the clear, accompanied by a signatureapplicable to the combination of the personalization data and randomchallenge. Modem processor verifies the signature, checks that thereceived challenge from apps processor is the same as the one that wassent by modem processor, and if both verification and challenge aresuccessful, modem processor uses the personalization data.

Method 2 has the modem send a random challenge accompanied by anencrypted Session Key generated by the modem processor and encryptedwith Public Key possessed by modem processor. Apps processor decryptsthe encrypted Session Key to recover the Session Key. Apps processorsends back the random challenge to modem processor in a data structure.Apps concatenates Personalization Data (the permissions portion) withthe challenge and sign the whole thing. Apps processor encryptspersonalization data with Session Key and sends the encryptedpersonalization data in the data structure too. The data structure issigned and thus accompanied by the Signature. Modem processor checks therandom challenge reply, verifies the Signature, uses modem's own SessionKey to decrypt the encrypted personalization data, and then modemprocessor uses the personalization data.

Method 2 Summary (authentication and confidentiality required):

Apps Processor Sends:

1—Personalization data encrypted with Session Key2—Challenge received from modem processor3—Signature applicable to combination of 1 and 2

Modem Processor then does the Following:

1—Verifies signature2—Checks that the received challenge is the one that was sent3—If both steps 1 and 2 are successful, modem processor decryptspersonalization data with symmmetric key and uses the personalizationdata. Otherwise, do not use.

Method 3: Same as Method 2 except the encrypted Session Key does doubleduty as both itself and as the random challenge. The random challenge isconstituted by the encrypted Session Key. The random challenge is notonly decrypted to obtain the Session Key for encrypting thepersonalization data, but also the random challenge is sent back by appsprocessor to modem processor in the form received from modem processor.

Description now turns specifically to the further Figures.

In FIG. 3, modem processor 200 has modem software 2010 such as cellular,WLAN, wireline or other modem software. Modem processor 200 two-waycommunicates with applications (apps) processor 600 using a mailboxregister 2020 in modem processor 200, over communications path 2030, andusing a mailbox register 2040 in apps processor 200. A mailbox structureherein includes, for example, hardware registers 2020 and 2040, accessby each processor into the processors register space, and interruptservice routines in each processor for servicing the accesses. Forexample, communications path 2030 is suitably provided by the pathsignified by Arrow “B” in FIGS. 2A and 2E.

The mailbox approach is particularly useful for integrated circuitshaving the modem processor 200 and the apps processor 600 on the samechip as in threat Type 2 listed hereinabove. Other communications pathssuitable for various architectures having one chip or multiple chipsinclude interrupt-based communications through interrupt controlregisters, and serial communications through MCSI multi-channel serialinterface or UART or McBSP multi-channel buffered serial port.

When either processor 200 or 600 sends a message to the other processormailbox 2040 or 2020 as destination, the message is stored in thedestination mailbox register 2040 or 2020 and an interrupt is generatedin the destination processor 600 or 200. The interrupt signals thedestination processor to execute an interrupt service routine to processthe message that has been sent to the destination mailbox register.Further examples of information sent each way between modem processor200 and apps processor 600 are described in connection with FIG. 4 laterhereinbelow.

Further in FIG. 3, a service application 2050 includes an interruptservice routine for servicing the mailbox 2050 in apps processor 600.Service routine 2050 two-way communicates via a path 2060 with anoperating system driver 2070. The driver 2070 two-way communicates via apath 2080 with secure mode hardware 650 and Protected Applicationsoftware 2090 associated with hardware 650.

The service routine is, for instance, a combination of an interruptservice routine and a low level driver (sometimes called a physicaldriver). The interrupt service routine is used to identify the commandrequest from the modem processor 200 to application processor 600. Thelow level driver is used to receive and transmit IMEI deviceidentification and SIMLock subscriber identification data to and fromthe modem interface to the secure environment (SE) Driver that is thehigh level operating system (HLOS) driver) 2070.

At boot up, apps processor 600 authenticates its software and data suchas in SDRAM 632 and/or Flash memory 638, and via EMIF/CF block 630. Appsprocessor 600 then sets a Memory Lock register 2095 to lock down theauthenticated software and data by making the memory spaceswrite-protected in which they reside.

In FIG. 3A, a Device Bound Certificate (DBC) carries information insecure form for manufacturing the system components of FIG. 1 andoriginally loading, testing and running each system component 110, 110′,150, 160, 180, 190. The process of manufacture is described further inconnection with FIG. 9 elsewhere herein. The DBC includes a Public ChipID identifying the chip. This Public Chip ID is public identificationinformation derived from but not necessarily identical to theDevice-Unique Secret Key for the chip. The Creator ID identifies themanufacturer such as an original equipment manufacturer (OEM). TheApplication ID identifies the application. Next in the DBC is a hash ofthe bootstrap code and software certificate. Further provided is a hashof the modem software and software certificate. The DBC includes an IMEIcertificate, such as an encrypted IMEI for a cellular telephone handset.An HMAC hash message authentication code further protects the devicebound certificate DBC.

In FIG. 4, the diagram is divided into three parts. At left, relevantportions of the modem code reside in or are associated with modemprocessor 200. At right, an applications (apps) processor 600 hassecurity block 650 and apps processor code resident in or associatedwith the apps processor. Information, as shown in the middle of FIG. 4,is communicated back and forth between modem 200 and apps processor 600.The information and processes of FIG. 4 further detail the structuresand processes of FIG. 3.

In FIG. 4, a SIM locking (“SIMlock” herein) Public Key forencryption/decryption is generated by a key generator 2105 in a step2110 for the modem processor 200 by inserting that SIMlock Public Keyinto and storing it as part of the boot image loaded into the modemprocessor 200 at the factory which makes the modem processor 200. TheSIMlock Public Key is any suitable public key. In one form, the SIMlockPublic Key has the further feature of being unique to the modemprocessor 200 device. The SIMlock Public Key is either stored in flashor in the modem processor 200 as the skilled worker selects inaccordance with practical considerations. The Simlock Public Key isauthenticated at boot up of the modem processor 200.

Also, in a step 2120, a SIMlock Private Key corresponding to the SIMlockPublic Key is stored in hardware-protected secure space 650 of the appsprocessor 600. Suitable hardware protection is provided by a securestate machine 2260 of FIG. 5 for instance. Hardware protection is alsoaccomplished using the secure storage mechanism by encrypting data withthe Derived Key derived from the Device-Unique Secret Key and storing itin either public memory or secure RAM, or internal or external writablenon-volatile memory whether or not secure, or storing the data inportions allocated to any one or more of public memory, secure RAM andwritable non-volatile memory. This latter form of hardware protectioncan still be seen as “hardware protected memory” but differs from theapproach solely using secure RAM or ROM. Further in FIG. 4, the SIMlockPrivate Key is not shared with the modem processor 200 in thisembodiment, wherein the SIMlock Private Key is used in the appsprocessor 600 only and in the secure mode of the apps processor 600only.

An IMEI device identification 2122 is also stored in hardware-protectedsecure space 650 of the apps processor 600. Also in the secure space 650is a Security Control Register SECCTRL, which has Flash Memory Lock bits2126 for particular storage spaces and/or entire memories and analogousSDRAM lock bits 2128 for particular storage spaces and/or entirememories.

Further, in a step 2130, a SIMlock file 2135 is initially stored in theapps processor 600 secure memory space and encrypted by the SIMlockPrivate Key in a step 2132. Alternatively, in step 2130, a SIMlock file2135 is initially stored in the apps processor 600 secure storage andsuitably encrypted by a Symmetric Key derived from the Device-UniqueSecret Key in a step 2132. In either case, hardware protection is alsoaccomplished using the secure storage mechanism by storing the encryptedSIMlock file 2135 in either public memory or secure RAM or internal orexternal writable non-volatile memory whether or not secure, or storingthe data in portions allocated to any one or more of public memory,secure RAM and writable non-volatile memory.

The SIMlock file 2135 is changed or modified only in secure mode of theapps processor 600 by a security module 2190 accessible by userinterface 2195 for PIN (personal identification number) entry. Access ispermitted only if a PIN authorized for the apps processor 600 isprovided.

The SIMlock file 2135 is a table of row entries. Each row has entriesfor Lock Type, Permission, IMSI (International Mobile SubscriberInformation), a PIN and a Counter value. Lock Type represents respectiveways to lock access by world region, country, network operator, andother defined modes of scope of access. Permission represents whetherthe particular Lock Type is 100% accessible with all features, notaccessible at all (zero 0% features) to the user, or which features ofthe mobile phone are available to user when fewer than all features ofthe mobile phone are available. IMSI provides subscriber informationpertinent to each user who is permitted to use the mobile phone throughthe user's possession and insertion of a SIM card into the mobile phonehandset 110 to activate the handset 110 of FIG. 1.

In FIG. 4, respective row counters Ctr 2138 automatically record andkeep a record in SIMlock file 2135 of how many times the entries of eachgiven row have been changed by use of the PIN and entry of newinformation. Diagnostic software suitably determines if an unusualnumber or pattern of entry-changes have occurred.

Next in FIG. 4, the modem processor 200 and the apps processor 600 arebooted. In a step 2140, a random seed is generated by a high-qualityrandom number generator (RNG) in security block 650 of apps processor600 and supplied to modem processor 200.

In one category of embodiment, the modem processor 200 software istamper-proof and the apps processor 600 has a higher level of securitysuch as providing a hardware-protected secure mode of operation as inFIG. 5.

Further in FIG. 4, at boot up, the modem processor 200 software code anddata are authenticated. Also, the apps processor 600 software code anddata are authenticated. The objective is to foreclose and prevent thepossibility of unauthorized software being introduced and used to obtainaccess to features which are not permitted for a given user.

Any suitable authentication process is used at boot up of each processor200 and 600. For example, hashing the modem processor 200 software codeand data 2145 at boot up and comparing a hash value with a pre-computedhash value pre-stored in the boot image is one method of authentication.Obfuscation of the modem processor 200 software code and/or data issuitably used as a security measure alone or together with othersecurity measures in the modem processor 200.

Authentication is suitably performed not only at boot time, but alsoperiodically and/or non-periodically after boot time.

Further, the modem processor 200 code and data are locked at boot time.For example, each memory and/or memory space holding authenticated modemcode and data is locked in secure mode by setting Flash Lock bits 2126and SDRAM Lock bits 2128 in apps processor 600 to a locked state. Thesecure state machine 138 of FIG. 1, and FIG. 2E prevents writes to thelocked storage spaces and thereby provides hardware-based protection tothe locked storage spaces and to the Security Control Register and itslock bits 2126 and 2128. Modem processor 200 and apps processor 600 areable to read the locked storage spaces.

Alternatively or in addition, a Memory Lock Register 2148 is suitablyprovided in modem processor 200. The modem processor 200 has Memory LockRegister 2148 controlled by transferred and authenticated bits from theFlash Lock bits 2126 and SDRAM Lock bits 2128 from apps processor 600,for example. In the locked state, an MMU (memory management unit orMemory Controller of FIG. 2A) or similar circuitry of modem processor200 is made write-protected so that writes to such memory and/or memoryspace are disabled. Such memories include SDRAM (e.g., synchronousdynamic random access memory of DDR double data rate and othervarieties), Flash memory, and other memories and memory spaces on andoff-chip.

Advantageously, the authentication and locking processes described forthe modem processor 200 hereinabove prevent security attacks of varioustypes. If a memory is tampered with (e.g., alteration of contents,physical replacement, or adding or removing memory) prior to boot time,then the hash at boot up, computed by modem processor 200 on the modemcode and data, will not equal the pre-stored hash value in the bootimage of modem processor 200. If a memory is tampered with after boottime, then the hash in one or more post-boot security checks will notequal the pre-stored hash value in the boot image of the processor, suchas 200, which checks that memory. If equality is found, normal operationis resumed and continues. If equality fails, then software and hardwareof modem processor 200 are activated or bypassed as necessary to takeappropriate measures such as warning message on user display, retry,disablement of wireless communication such as preventing a requestedphone call, activation or initiation of an automatic call to enterprisesecurity center and/or IT support center, and/or system reset.

If the authentication process is unable to authenticate the modemprocessor software, then the modem processor 200 is returned to a resetstate. If the modem processor 200 software is successfullyauthenticated, then operations proceed to a step 2150.

In this embodiment, authentication by apps processor 600 is describedthe same as in the above four paragraphs as for modem processor 200. Theanalogous description is omitted for conciseness.

In step 2150, the modem processor 200 sends a random challenge 2155 tothe apps processor 600. The modem processor 200 is, in effect, requiringapps processor 600 by means of the challenge 2155 to prove that thedevice that constitutes apps processor 600 is in fact the one particularauthorized apps processor device with which modem processor 200 ispermitted to communicate.

To generate the challenge 2155, modem processor 200 code suitably runs apseudo-random number generator that starts the process of generating apseudo-random number symmetric key useful as a Session Key based on theRandom Seed provided by the apps processor 600 in step 2140. The SessionKey is based on some type of shared secret, in this case the RandomSeed. In this way, the modem processor 200 provides a challenge 2155that is generated sequentially starting from the Random Seed of step2140. If the modem processor 200 has a high quality random numbergenerator (RNG), then that RNG is suitably used. However, some types ofmodems have a lower level of security and a pseudo-random numbergenerator is adequate for generating the random or pseudo-random numberthat is sent from modem 200 for purposes of the random challenge to theapps processor 600. Alternatively, a time-stamp from the modem 200 issent as the challenge number.

The challenge step 2150 further advantageously thwarts replay attackswherein an earlier instance of communication from the apps processor 600is unauthorizedly intercepted and then sent in replayed or repeated forminto the modem 200 at a later time, to somehow take advantage of thefeatures of the modem 200 or to overload modem 200. Replay attacks arethwarted because the modem processor 200 at the later time will onlyrespond to a different form of the communication from apps processor 600than had occurred at the earlier time. This varying different form isdescribed further hereinbelow.

A communications step 2160 now occurs wherein the apps processor 600responds to the random challenge 2155. Apps processor 600 sends a filestructure 2170 that has several parts. First, a predetermined portion2172 from SIMlock file 2135 provides, for example, all rows of LockType, Permission, and IMSI. PINs from SIMlock file 2135 remain stored insecure space occupied by SIMlock file 2135 in apps processor 600 and arenot transmitted to the modem 200 processor in this embodiment.

Additionally, the file structure 2170 communicated by apps processor 600in step 2160 includes a reply field 2175 which, in one example,replicates random challenge 2155 earlier sent to apps processor 600 instep 2155. In applications where it is desired to avoid duplicating therandom challenge received by the apps processor 600 in the reply by theapps processor 600, then the random challenge is suitably encrypted withby the apps processor in any suitable way that can be decrypted by themodem processor 200.

If the returned random challenge 2175 of step 2160 matches the sentrandom challenge 2155 of step 2150, then the challenge has beenfulfilled by apps processor 600 and modem processor 200 confirms thisevent by verification of the match.

File structure 2170 further includes a Signature 2178. Apps processor600 suitably generates the Signature 2178 in any appropriate securemanner such as by first performing a hash of the combination of theSIMlock file portion 2172 combined with the random challenge field 2175.Then, second, the resulting hash value H600 is encrypted with theSIMlock Private Key that was provided to apps processor 600 in step2120. Hash value H600 is thus encrypted with the SIMlock Private Key toconstitute Signature 2178 and, the Signature 2178 is sent with the filestructure 2170 to the modem processor 200.

Further in FIG. 4, a step 2180 is performed by modem 200. Step 2180verifies the integrity of the file structure 2170 sent by apps processor600 to modem 200. Step 2180 verifies integrity of file structure 2170using the random challenge information in field 2175 as discussed aboveas well as by using the SIMlock Public Key (PUB KEY) which was stored byapps processor 600 in modem 200 in step 2110. Step 2180 also decryptsthe Signature 2178 using the SIMlock Public Key to recover the hashvalue H600 that was encrypted into the Signature 2178.

An asymmetric encryption/decryption process is used so that encryptionoccurs in apps processor 600 using the SIMlock Private Key anddecryption is successfully completed using the SIMlock Public Key (PUBKEY).

Then Modem 200 itself independently hashes the combination of fileportion 2172 and random challenge field 2175 to produce a hash valueH200 by modem 200 independently of the hash value H600 that was computedby apps processor 600 earlier and that H600 was sent encrypted in theSignature 2178. The hash value H600 recovered from Signature 2178 iscompared with hash value H200 independently computed by modem 200 on thereceived material including file portion 2172 and random challenge 2175combined.

If and when modem processor 200 determines that hash value H600 equalsand is the same as hash value H200, then integrity of file structure2170 is confirmed. The Lock Type, Permission, and IMSI data arethereupon used by modem processor 200 to activate features and enableaccess to communications in accordance with the Lock Type and Permissioninformation in file portion 2172. This activation pertains only to theuser when the user has provided and inserted a SIM card 295 of FIG. 2Ainto the handset which identifies and confirms the user as authorized,provided modem processor 200 verifies by successful match or othercomparison of data from the SIM card with the IMSI data.

If hash value H600 does not equal or is not identical with hash valueH200, then file structure 2170 lacks integrity or has an unconfirmedlevel of integrity. In such case, software in modem processor 200 issuitably coded and executed to repeat the steps 2150 and 2180. Step 2150causes another response step 2160 from apps processor 600 to sendanother file structure 2170 for verification by modem processor 200 instep 2180. Unless the verification is successful within a small numberof repeated attempts (e.g., one or two), the modem processor 200 andapps processor 600 are forced to reset. Alternatively, the software inmodem processor 200 is coded to force an immediate reset without anyrepeat attempt at all.

Software and hardware are activated or bypassed at challenge-checkingand hash value-checking 2180 time to take appropriate measures. Suchmeasures include warning message on user display, retry, disablement ofwireless communication such as preventing a requested phone call,activation or initiation of an automatic call to enterprise securitycenter and/or IT support center, and/or system reset.

Unauthorized activity might attempt to directly introduce or inject abogus file structure 2170 into modem processor 200, bypassing step 2180and thereby to cause modem processor 200 to respond to the bogus filestructure to obtain unauthorized accesses and features. Suchunauthorized activity is thwarted because software alteration of thesoftware executed by modem processor 200 is required to bypass the step2180 decryption and equality checks established and described. Suchsoftware alteration requires tampering which is detected or prevented bythe authentication and/or locking features established and describedearlier hereinabove wherein modem processor 200 code and data areauthenticated and locked at boot time and authenticated at intervalsafter boot time. In other words, the hash of the modem processor 200software and data fails to pass the hash checking at and/or after boottime when such unauthorized activity occurs. Software and hardware areactivated or bypassed as necessary to take appropriate measures such aswarning message on user display, retry, disablement of wirelesscommunication such as preventing a requested phone call, activation orinitiation of an automatic call to enterprise security center and/or ITsupport center, and/or system reset.

In security module 2190, a secure software program is provided by whichan authorized user is provided with a Personal Identification Number(PIN) 2195 which matches the PIN stored for that IMSI user SIM card 295(FIG. 2A) in a row 2136 of Simlock file 2135 of FIG. 4. Provided thatthe SIM card 295 provided and inserted by user supplies data PIN 2195matching the IMSI user data in row of 2136 of SIMlock file 2135, andfurther provided that the PIN entered by user matches the stored PIN inrow 2136 of SIMlock file 2135, then user is further permitted to modifyone or more of the fields of Lock Type, Permission, IMSI, PIN andCounter Ctr. If the foregoing proviso conditions are not all met, thenthe user is denied the modification code and disabled from making anymodifications, and the system takes appropriate measures such as warningmessages, retry, branch to ordinary use of the handset, automatic callto enterprise security center, and/or system reset.

Similar PIN arrangements or additional PINS and software to respond tosuch PINS are suitably included in or associated with apps processor 600to enable an authorized administrator and/or supervisory authorizedperson to alter the SIMlock file for additional fields and users otherthan themselves. In this way personalization to restrict the scope ofpermitted accesses, features and users is permitted. Conversely, the PINarrangements support de-personalization to expand the scope of permittedaccesses, features and users.

In various embodiments, the security features described here are appliedto

A. Mobile phones having a less-secure but tamper-resistant processor ona different chip from a more secure processor with hardware securityfeatures.

B. Mobile phones having a less-secure but tamper-resistant processor onthe same chip as a more secure processor with hardware securityfeatures.

C. Mobile phones having two processors each on different chip and bothhaving a very secure processor with hardware security features.

D. Mobile phones having two processors each on the same chip and bothhaving a very secure processor with hardware security features.

E. Mobile phones of varieties A, B, C, D above wherein the data is SIM(subscriber identification module) data

F. Mobile phones of varieties A, B, C, D above wherein the data is DRM(digital rights management) data or any other data which needs to bemaintained in a secure manner.

G. Mobile phones with WLAN (wireless local area network, e.g. 802.11,etc.) modem and/or wireless cellular or packet voice/data modem in themobile phone.

H. Personal computers, laptop computers, handheld computers, and otherportable computers in public places such as kiosks and in enterprise andother private locations wherein user identification data, digital rightsmanagement data, and/or any other data needs to be maintained in asecure manner and wherein one processor communicates locally or remotelywith another processor.

I. DSL (digital subscriber line) and/or WLAN routers and gateways instand alone gateway configurations and/or computer units.

J. Wireless base stations.

K. Any application where two or more at least partially secureprocessors need to handle identification data, rights data, and otherdata in a secure manner.

The improvements described herein are applicable to processors of manymanufacturers.

ME personalization is the process of storing information in the ME andactivating the procedures which verify this information against thecorresponding information stored in the SIM/USIM whenever the ME ispowered up or a SIM/USIM is inserted, in order to limit the SIM/USIMswith which the ME will operate.

Five personalization categories of varying granularity include: Network,Network subset, Service Provider, Corporate, and SIM/USIM.

The personalization categories are independent in so far as eachcategory can be activated or de-activated regardless of the status ofthe others. Each category has a separate personalization indicator toshow whether it is active or not. The ME can be personalized to onenetwork, one network subset, one SP, one Corporate, one SIM/USIM or anycombination thereof. The ME may optionally be personalized to multiplenetworks, network subsets, SPs, Corporates, IMs or any combinationsthereof

Each of the personalization categories uses thus three types ofinformation (referred further as the ME personalization information)which are securely stored in the ME: 1) one or more personalizationcodes that will be checked against the information stored on theinserted SIM/USIM card, 2) an indicator to show whether it is active ornot, and 3) a key used as the password for its de-activation.

All those information items are protected from tampering/modification.Additionally the de-personalization keys are unique for differentdevices (e.g., per-device bound Derived Keys). Hardware-based securitybinds the IMEI device identification to the physical device. Thede-personalization keys are prepared by a process based on particulardevice identifications to make the de-personalization keys per-devicebound.

Various threats to the ME Personalization Information include Threat1—Tampering of ME personalization Data. If the ME Personalization datais tampered with, then any SIM/USIM could be inserted and the phonecould connect to any network, service provider etc. Threat 2—FlashReplacement Attacks. If the ME Personalization data is stored in FlashMemory and the whole Flash Memory part is replaced, the MEPersonalization data is indirectly tampered with. Thus the MEpersonalization data is desirably made device bound.

The processes and methods described herein advantageously addressvarious threats.

Type 1 and Type 4 Devices—ME protection Using a Generic CommunicationProtocol

The Modem side software, which needs the ME Personalization Informationrequests for this information from the Apps processor side using aMailBox between the processors. This request is passed on from the otherend of the MailBox to a service routine on the Apps processor side. TheApps Processor stores the ME personalization information in the form ofa ME personalization certificate (which contains the necessary MEpersonalization data and status flags has been signed with the OEM/keyor any other similar key)

The PA does the necessary validation of the ME personalizationCertificate (MEPC, similar to the IMEI certificate described in FIG. 3A)and sends the relevant ME personalization data MEPD)(like statusindicator) to the driver. If the ME personalization certificate MEPCcannot be validated. Note that the MEPC is also device bound.

De-Personalization of the ME Personalization data is performed at theApps processor and the changes are executed inside Secure Mode.De-personalization is prevented from being performed other than by theapps processor and prevented outside of secure mode.

For the type of devices with integrated apps and modem processor, thecommunication protocol is slightly simplified. The steps to security aredescribed in the following two process embodiments. The target, hostmachine and secure server of FIG. 9 are suitably provided.

Integrated Apps/Modem: Security Process 1

1. Flashing:

a) The target sends out the Public ID to the Host Machine

b) The Host Machine embeds the Public ID to the Secure Server over asecure tunnel (channel).

c) Simultaneously, the Host Machine also sends the Flash Loader down tothe target.

d) The secure server generates the ME personalization certificate (MEPC)signed with the OEM public key and that is sent down to the host machineand then to the target.

e) The Flash Loader uses a PA to verify the MEPC and removes thesignature on the MEPC and replaces it with a new (modified) MEPC, whichis both encrypted and HMACed with a Derived Key such as a symmetric keyderived from the Device-Unique Secret Key and stores this in flash. Insome embodiments, only the depersonalization key portion is encrypted.

f) The Flash Loader in step 2105 of FIG. 4 also generates a Private Key,Public Key pair (using a PA). The Private Key is stored in step 2120inside secure mode (if secure storage is not available, it is storedencrypted using a Derived Key derived from Device-Unique Secret Key) andthe Public Key is made a part of the Modem Software (SW) (GSM/GPRS/EDGEWCDMA/UMTS or other suitable modem Code). One or more Derived Keys andother keys are suitably stored in secure mode hardware-protected lockedstorage, or in originally-manufactured ROM, or in write-once storagesuch as E-Fuse, and appropriately protected by the security statemachine 2260.

g) The Flash loader also loads the Modem SW (with the correspondingPublic Key) into Flash Memory and locks them using GSM Flash Protect.

h) The Flash Loader also creates a data structure 2130 called the MEpersonalization data (MEPD, which is in clear-text and contains allpublic information but not the Derived Key depersonalization keys) andsigns the MEPD with a Signature hash value encrypted with the PrivateKey from step 2120 stored inside Secure Mode and loads it into flashmemory.

2. Booting and Run-Time:

a) While booting, the BootStrap uses its PA to authenticate the Modem SWCode segment and the new (modified) MEPC certificate (by decrypting andcomputing the HMAC using a Derived Key derived from the Device-UniqueSecret Key). The PA again signs the MEPD data and stores it in flash(this signing step may be omitted) along with the Random Seed generatedby the high-quality random number generator and the Modem SW is releasedfrom reset and executed.

b) At run-time all changes to the ME personalization data MEPD, whichhappen either through a user interface 2190 of FIG. 4 or through anauto-lock triggered mechanism are dealt with on the Apps Processor sidein the following two steps:

i) Using an OS driver which loads a Protected Application, the MEPCcertificate (which is encrypted and HMACed) inside Secure Mode isupdated and a new HMAC is computed and the data is encrypted again.

ii) The MEPD data (with the public information, some of which may benew) is again re-signed with a Signature such as hash value encrypted bythe Private Key inside Secure Mode and is saved in Flash Memory.

3. Modem Side.

a) The Modem SW is prevented from tampering because of the Flash WriteProtect mechanism. Whenever the Modem SW wants to use the MEpersonalization data MEPD, it issues a challenge and verifies thesignature on the response coming from the Apps SW before using the MEPD.See FIG. 4.

b) The Modem side SW also sends any relevant triggers to the AppsProcessor (example auto-lock trigger AT). This may be done using an ATcommand interface.

Integrated Apps/Modem: Security Process 2

This process is suitably used if there is no OS driver 2070 available.

1. Flashing: (same steps as in process 1 Flashing)

2. Booting and Run-Time:

a) While booting, the BootStrap uses its PA to authenticate the Modem SWCode segment and the new (modified) MEPC (by decrypting and computingthe HMAC using a Derived Key derived from the Device-Unique Secret Key).Flash loader again signs the MEPD and stores it in flash along with arandom number seed generated by the high-quality random number generatorand the Modem SW Code is released from reset.

b) At run-time all changes to the ME personalization data MEPD, whichhappen either through a user interface 2190 of FIG. 4 or through anauto-lock triggered (AT) mechanism are dealt with by storing them eitherencrypted by the Private Key or the new data in permanent secure storageand then forcing a reboot of the system. This is suitably enhanced evenmore by encrypting the stored value with the Public Key from the Modemside. The Private key on the Apps Processor side is suitably used todecrypt the values inside Secure Mode when the device reboots.

i) When the system reboots, the Boot Strap reads the saved value (ofeither the Private Key or the Personalization data MEPD from permanentstorage) and the MEPC is modified (inside Secure Mode) and the MEPCcertificate is again re-signed with the new values.

3. Modem Side. (same steps as Security Process 1).

FIG. 5 illustrates an advantageous form of software modes andarchitecture 2200 for the secure apps processor 600. Encrypted securestorage 2210 and a file system 2220 provide storage for thisarrangement. Selected contents or all contents of encrypted securestorage 2210 are further stored in a secure storage area 2225.

Next a secure mode area of the architecture is described. In a ROM areaof the architecture 2200, secure ROM code 2240 together with secure datasuch as Device-Unique Secret Key and other cryptographic key data aremanufactured into an integrated circuit including processor circuitry.Also a secure RAM 2245 is provided. Secret data such as key data iscopied or provided into secure RAM 2245 as a result of processing of theSecure ROM Code 2240. Further in the secure mode area are modules forRoot Public Key, Random Key module such as for Device-Unique Secret Keyand producing Derived Key(s), RNG (Random Number Generator), SHA-1/MD5hashing software and processes, DES/3DES (Data Encryption Standardsingle and triple-DES) software and processes, AES (Advanced EncryptionStandard) software and processes, and PKA (Private Key Authentication)software and processes.

A hardware-implemented secure state machine 2260 monitors the buses,registers, circuitry and operations of the secure mode area of thearchitecture 2200. In this way, addresses, bits, circuitry inputs andoutputs and operations and sequences of operations that violatepredetermined secure standards of operation of the secure mode area aredetected. The secure state machine 2260 then provides any or all ofwarning, denial of access to a space, forcing of reset and otherprotective measures. Use of independent on-chip hardware for securestate machine 2260 advantageously isolates its operations fromsoftware-based attacks.

An addressable secure control register (SECCTRL) 2265 with some bits astabulated in TABLE 1 is provided in secure space.

TABLE 1 SECURE CONTROL REGISTER BIT/FUNCTION SECCTRL Bit/Function MPUJTAG serial scan testing enable control register. 1: MPU JTAG is enabled0: MPU JTAG is disabled SHA-1 hashing module access control register. 0:SHA-1 module access in non-secure mode and secure mode is enabled 1:SHA-1 module access in secure mode only is enabled DES/3DES encryptionmodule access control register. 0: DES/3DES module access in non-securemode and secure mode is enabled. 1: DES/3DES module access in securemode only is enabled. RNG true random number generator module accesscontrol register. 0: RNG module access in non-secure mode and securemode is enabled. 1: RNG module access in secure mode only is enabled.FLASH LOCK SPACE 1 Lock = prevent write access 0: no lock 1: lock FLASHLOCK SPACE i . . . Lock = prevent write access 0: no lock 1: lock FLASHLOCK SPACE N Lock = prevent write access 0: no lock 1: lock SDRAM LOCKSPACE 1 Lock = prevent write access 0: no lock 1: lock SDRAM LOCK SPACEi . . . Lock = prevent write access 0: no lock 1: lock SDRAM LOCK SPACEN Lock = prevent write access 0: no lock 1: lock

Secure state machine 2260 monitors busses and other hardware blocks, pinboundary and other parts of the chip for security violations andprotects and isolates the protected areas. Secure state machine 2260makes secure ROM space inaccessible, Security Control Register SECCTRL2265 inaccessible, and secure RAM space inaccessible and establishes anyother appropriate protections to additionally foster security. In oneembodiment such a software jump from flash to secure ROM, for instance,causes a security violation wherein, for example, the secure statemachine produces an automatic immediate reset of the chip. In anotherembodiment, such a jump causes the security monitoring logic to producean error message and a re-vectoring of the jump away from secure ROM.Other security violations would include attempted access to SecurityControl Register SECCTRL 2265 or attempted access to secure RAM space.

In FIG. 5, a kernel mode part of the software architecture includes oneor more secure environment device drivers 2270. Driver 2070 of FIG. 3suitably is provided as a secure environment device driver in kernelmode.

Further in FIG. 5, a user application 2280 communicates to and through asecure environment API (application peripheral interface) softwaremodule 2290 to the secure environment device driver 2270. Both the userapp 2280 and API 2290 are in a user mode part of the softwarearchitecture.

A protected application 2090 provides an interface between userapplication 2280 and information in file system 2220, secure storage2225, and a trusted library 2295 such as an authenticated library ofsoftware for the system.

Turning to FIG. 6, secure booting and flashing operations in appsprocessor 600 commence with a BEGIN 2305 and proceed to boot beginningwith a step 2310 that starts in a CS0 (chip select zero) memory space inon-chip ROM. Next, a step 2315 checks eFuse bits called Production IDbits. If these Production ID bits have a predetermined value such as 00,operations branch to Other Code step 2318. Otherwise, operations go to aSecure Boot sequence 2320.

Next, a succeeding step 2340 commences a secure mode entry sequence. InFIG. 6, a secure mode entry sequence 2340 of instructions and/or data isestablished. The security state monitor logic 2260 is arranged in itshardware monitoring function correspondingly to detect whatever thatSecure mode entry sequence of instructions and/or data has beenestablished to be. The secure mode is entered at step 2340 by secure ROMcode execution of the Secure mode entry sequence of instructions and/ordata. The Security state monitor 2260 checks the Secure mode entrysequence of instructions and/or data. Since this Secure mode entrysequence of instructions and/or data has been pre-programmed bymanufacturer in the correct authorized manner, the ROM code enterssecure mode. No user application operates at this time because securecode is executed, not user application code.

A further step 2350 executes ROM code authentication and authenticatesXLoader/2^(nd) boot code and flash loader, for flash and other memoryauthentication such as described in FIG. 4 and FIG. 5. References to“2nd” mean a Flash Loader software in the apparatus (such as a wirelesshandset). The Flash Loader loads software external to the apparatus viaa serial interface (e.g., SSI, UART, or USB) into a flash memory in theapparatus. References to “X Loader” mean bootstrap code that loads therest of the code into Flash memory.

Then a step 2360 exits secure mode. Exit from Secure mode at step 2360of FIG. 6 makes secure ROM space inaccessible, Security Control RegisterSECCTRL inaccessible, and secure RAM space inaccessible and establishesany other appropriate protections to additionally foster security. Insome embodiments, any subsequent attempts to enter secure mode, even bythe special Secure mode entry sequence of instructions and/or data, isdetected as a security violation and protective measures followimmediately. For example, this approach is suitably used where allsecure mode operations such as updating of data 2135 of FIG. 5 arerequired to occur by forced reboot. In other embodiments, specifiedoperations such as updating of such data are permitted to occur atrun-time and enter secure mode.

Next, a step 2370 executes the now-authenticated XLoader/2^(nd) bootcode and Flash loader. Operations proceed on at CONTINUE 2380 to executeapplications. Secure mode is suitably reentered as needed to accomplishsecure operations such as protected applications 2090 of FIG. 3 and aselsewhere described herein.

The process, structure and description of FIG. 4 earlier hereinabove isnot only applicable to improved security and communication between onemodem processor 200 of FIG. 2A and one secure application processor 600of FIG. 2E. FIG. 4 and its processor, structure and description hereinapply to cases where 1) there is more than one modem processor and/or 2)the security functionality is split between several processing elementsthat are suitably smaller, or occupy other relative amounts of realestate compared to each modem processor or all modem processorscombined. Distributed processing confers performance and power-savingadvantages in systems as described further herein.

Turning to FIG. 7, a system has a secure application processor 2510 andat least two modems having one or more processors and memory. Coupled tosecure apps processor 2510 is a first 2.5G (2.5 generation wireless)modem 2520, and a further 3G (third generation wireless) modem 2530.Additionally, other modems, modem processors, and other wireless andfull-feature processors are provided in blocks 2540 and 2550, etc., andalso coupled to the secure apps processor 2510. For example, a furtherwireless modem 2540 (e.g., WLAN 802.11 as in FIG. 2G and/or ultrawideband UWB 802.15.3) is or are provided. A video processor 2550 hasDRM functionality enhanced as described herein by secure apps processor2510. In this example, one, some or all of the processors 2520, 2530,2540, 2550, etc. have no built-in security or less built-in securitythan the secure apps processor 2510.

Secure apps processor 2510 locks down certain regions of each modemmemory in or associated with any one, some or all of the modems andblocks 2520, 2530, 2540, 2550, etc. Secure apps processor 2510 locksdown those regions of modem memory from external access therebyproviding a tamper proof environment. A secure firewall capability isalso suitably used for the lock-down process. The secure apps processor2510 communicates with each of the modems and blocks 2520, 2530, 2540,2550, etc. in the manner described and shown in connection with FIGS. 3,4, 5 and 6 hereinabove.

The system of FIG. 7 is suitably provided on five chips—one chip perprocessor and modem block of the illustration. In other embodiments, thetwo or more or all of the blocks of FIG. 7 are integrated onto the samechip so that the system is provided in four, three, or two chips of amulti-chip system. In the most highly integrated form, the system ofFIG. 7 is provided on one single integrated circuit chip having cores orregions as shown, and the secure apps processor 2510 is a highly secureregion or block among a number of less-secure regions or blocks on thesingle integrated circuit chip.

In the system of FIG. 7, and with the processes of FIGS. 3, 4, 5 and 6suitably combined thereinto, the apps processor 2510 initializes andauthenticates the memory contents of each modem 2520, 2530, 2540, 2550,etc. separately, either sequentially or substantially parallelizingsecure communications, including providing each modem with a Public Key(the public/private key pair can either be the same for each modem, ordifferent), and a different Random Seed. See steps 2110 and 2140 of FIG.4. The secure apps processor 2510 then activates the memory protectionmechanism and each modem then has its own respective authenticatedcommunication mechanism with the secure apps processor 2510.

In FIG. 7, each of the modems and blocks 2520, 2530, 2540, 2550, etc.challenges the secure apps processor 2510 as in step 2150 of FIG. 4.Secure apps processor 2510 responds with a signed file structure, as instep 2160 of FIG. 4, to the challenge from each of the modems and blocks2520, 2530, 2540, 2550, etc. of FIG. 7. The system architecture of FIG.7 is suitably extended to any number of blocks 2520, 2530, 2540, 2550,etc. which are called “security client processors” herein, working withmore secure block 2510 called a “security provider processor” herein.

In FIG. 8, the secure processing is partitioned among two or more secureprocessors 2810.11, 2810.12, 2810.21, 2810.22 etc. The secure processorshave an array or grid-like structure, or a linear structure 2810.11, . .. 2810.1N, or an even more complex structure. Similarly, the modem andother less-secure processing is provided in an array structure 2820.11,2820.12, 2820.1N, . . . , 2820.M1, . . . 2820.MN where M and N arecounting numbers. If M=N=1, then there is a single modem processor2820.11. If M=2 and N=4, then eight modem and other processors 2820.11through 2820.24 are provided as shown in FIG. 8.

A particular example of the system of FIG. 8 includes a modem processor2820.11 and multiple secure processors 2810.11 and 2810.12 at least. Oneof the secure processors 2820.11 performs boot-time (initialization andauthentication and memory locking) aspects 2140 of the security processof FIG. 4. Each modem processor 2820.11, etc. performs the randomchallenge step 2150 to another secure processor such as processor2810.12. Such other secure processor 2810.12 acts as a secure storagemodule where the SIMlock file 2135 is stored and information therefromsupplied in step 2160. Each modem processor 2820.11, etc. of FIG. 8performs integrity verification of step 2180 of FIG. 4.

In other embodiments the various steps of a secure processor in FIG. 4are performed by one, some, or all of the secure processors 2820.11,etc. in FIG. 8. Also, the various steps of a modem processor in FIG. 4are performed by one, some, or all of the less-secure modem and otherprocessors 2820.11, 2820.12, etc. in FIG. 8.

In FIG. 9, a target 2910 includes an architecture having at least oneless-secure modem processor portion and at least one more-secure appsprocessor portion. Target 2910 is suitably implemented as in any of FIG.3, 7 or 8 or otherwise as described herein. Target 2910 is coupled to amemory 2920 including a flash or other memory for holding MEPCcertificate, MEPD data, and Modem SW as described earlier hereinabove.

In FIG. 9 a host machine 2930 is coupled both to target 2910 and to asecure server 2940. Host machine 2930 provides a Flash Loader and adevice bound certificate (DBC) of FIG. 3A including the MEPC certificateto Target 2910 in response to a public ID from target 2910 andauthorization and MEPC certificate from secure server 2940.

In some embodiments, a method of providing data security includes,storing data in a first memory of a first processor havinghardware-based security, operating a second processor to authenticatethe data in the first processor, and operating the first processor tosend the data from the memory of the first processor to a second memoryexternal to the first processor. The authentication can be performedbefore, after or concurrently relative to when the data is sent.Operating the first processor to send data suitably also leaves theoriginal data in the memory of the first processor. In some embodiments,the second memory is either in or associated with the first processor orinstead in or associated with the second processor. In some embodiments,the authenticated data is sent directly from the first memory to thefirst processor for processing. The second memory is accessible by thesecond processor and the first processor is operated to send the data ina confidential manner. As a result, more secure inter-processorcommunication occurs.

In an embodiment, a system includes a modem processor that is capable ofsecure boot in that the modem processor authenticates and initializesits own contents. The modem processor generates a random seed at boottime or, a new random number at run-time, each time the seed or randomnumber is needed. The modem processor in this embodiment lacks anability to access secure storage locally, however. Further, in thisembodiment, SIMlock protection is not already part of a custom ROM codeof the modem processor. Then, an external, secure (applications)processor is further provided. For accessing secure storage, the modemprocessor having the functions and functional constraints just describedrelies on the resources of the external secure (application) processorusing the process and system described hereinabove in connection withFIGS. 3 and 4.

It is emphasized here that while some embodiments may have an entirefeature totally absent or totally present, other embodiments, such asthose performing the steps of FIGS. 3, 4, 5 and 6 have more or lesscomplex arrangements that execute some code portions, selectively bypassothers, and have some operations running concurrently sequentiallyregardless.

A few preferred embodiments have been described in detail hereinabove.It is to be understood that the scope of the invention comprehendsembodiments different from those described yet within the inventivescope. Microprocessor and microcomputer are synonymous herein.Processing circuitry comprehends digital, analog and mixed signal(digital/analog) integrated circuits, ASIC circuits, PALs, PLAs,decoders, memories, non-software based processors, and other circuitry,and digital computers including microprocessors and microcomputers ofany architecture, or combinations thereof. Internal and externalcouplings and connections can be ohmic, capacitive, direct or indirectvia intervening circuits or otherwise as desirable. Implementation iscontemplated in discrete components or one or more fully integratedcircuits in any materials family and combinations thereof. Variousembodiments of the invention employ hardware, software or firmware andcombinations of any of them. Process diagrams herein are representativeof flow diagrams for operations of any embodiments whether of hardware,software, or firmware, and processes of manufacture thereof

While this invention has been described with reference to illustrativeembodiments, this description is not to be construed in a limitingsense. Various modifications and combinations of the illustrativeembodiments, as well as other embodiments of the invention may be made.The terms “including”, “includes”, “having”, “has”, “with”, or variantsthereof are used in either the detailed description and the claims todenote non-exhaustive inclusion in a manner similar to the term“comprising”. It is therefore contemplated that the appended claims andtheir equivalents cover any such embodiments, modifications, andembodiments as fall within the true scope of the invention.

What is claimed is:
 1. A process of operating a mobile device thatincludes a modem processor and an application processor, the applicationprocessor storing sensitive data using hardware based security,comprising: A. validating the sensitive data on the applicationprocessor with protected applications. B. sending a request forsensitive data from the modem processor to the application processor; C.receiving the request in the application processor; D. passing therequest to a driver in the application processor; E. passing the requestfrom the driver to a protected application in the application processor;F. validating the sensitive data in the protected application; G.sending the validated sensitive data through the driver, and the serviceroutine to the modem processor.
 2. The process of claim 1 in which thesensitive data includes an International Mobile Equipment Identifier,which identifies the mobile device.
 3. The process of claim 1 in whichthe sensitive data includes Subscriber Identity Module personalizationdata, which identifies a smart card of the user in GSM wireless.
 4. Theprocess of claim 1 including running the protected application in ahardware based secure execution environment of the applicationprocessor.
 5. The process of claim 1 including running the protectedapplication in a hardware based secure execution environment of theapplication processor, and accessing the protected application through asoftware interface using a driver in the application processor.
 6. Theprocess of claim 1 including using a mailbox for communication betweenthe modem processor and the application processor.